From Wikipedia, the free encyclopedia

An uncia
(plural: unciae) is an ancient
Roman unit of length that roughly corresponds to an inch. One uncia is 0.97 inches or 24.6 millimeters. There are twelve uncia in one pes.

The word uncia was
Latin for a unit equal to 1/12 of another unit. The words
inch (1/12 of a foot) and ounce (originally 1/12 of a pound and still
1/12 of a troy pound) are derived from the word
uncia.